Bone fixation devices are well known and they find particular utility in the field of orthopaedic surgery, where they are used to fix a bone, which has sustained a fracture, across the fracture site.
The use of bone fixation devices, such as intramedullary nails, allows the fixing of a bone, without the need to surgically expose the fracture site of the bone, thus permitting minimally invasive surgery. An alignment jig connected to the intramedullary nail facilitates the targeted placement of transfixing screws or bolts with respect to the intramedullary nail.
In use, bone fixation devices, such as intramedullary nails, are connected to an alignment jig to facilitate targeted placement. Commonly, the alignment jig is connected to the bone fixation device by a threaded connecting bolt, the threaded portion of which engages with the bone fixation device and is securely, but reversibly, connected to the bone fixation device.
In use, an alignment jig is connected to the bone fixation device at the distal end of the alignment jig, usually close to and in line with the connecting end of the bone fixation device; whereas an operator, for example an orthopaedic surgeon, is located at the proximal end of the alignment jig. A wrench or spanner is usually used to connect or disconnect the alignment jig and the bone fixation device; wherein the wrench or spanner has to be skillfully guided deep into the surgical field in order to be used.
In certain situations of use, such as in large or obese patients, and in the region of the proximal femur, the interface between the distal end of the alignment jig and the bone fixation device may be located deep within the surgical field, within the patient.
Moreover, with respect to certain bone fixation devices, there is a need to operate a subcomponent of the bone fixation device at the connecting end of the device (at the distal end of the alignment jig), for example, axially advancing or retracting a setscrew for locking a transfixion bolt. Such operation may also involve the skilful freehand insertion of an instrument or tool deep into the surgical wound in order to reach the subcomponent of the bone fixation device.